#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using dt = array<int, 2>;

void test() {
  int a, b, c;
  cin >> a >> b >> c;

  if ((a % 2) == (b % 2)) cout << c << "\n";
  else if ((a % 2) == (c % 2)) cout << b << "\n";
  else cout << a << "\n";
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int T = 1;  
  // cin >> T;
  for (int i = 1; i <= T; i++) {
    test();
  }
  return 0;
}